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    <title>Document</title>
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    <script>

        // constructor  构造器

        const arr = [1,2,3] ;
        console.log(arr.constructor);

        function Dog() {}

        const d = new Dog() ;
        console.log(d.constructor);   // Dog


        console.log(d.__proto__)   // Dog.prototype


        // instanceof  血缘关系
        console.log(d instanceof Dog);  // 判断是不是某个构造函数的实例化对象

    </script>
    
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